Presymptomatic Testing for Huntington's Disease in Mexico: 28 Years of Experience.

Introduction: Huntington's disease (HD) is a genetic neurodegenerative disorder with dominant inheritance. Our center in Mexico City has offered presymptomatic testing (PT) since 1995.

Objective: To describe the main clinical and demographic characteristics of at-risk HD individuals who applied to the PT program, the reasons for seeking it, and the molecular results.

Methods: A cross-sectional study was conducted with sociodemographic and clinical data of all PT applicants from 1995-2023. Reasons for seeking PT were assessed using a modified questionnaire. In addition, anxiety, and depressive symptoms before and after PT were evaluated with Beck's instruments; cognitive impairment (CI) was assessed with the Mini-Mental State Examination (MMSE) and molecular results.

Results: 214 people applied for PT (2.1% of the at-risk population identified in our center); 63% were women (mean age of 37.11 years). 204 (95.3%) were accepted and 190 received results. 70% indicated that the main reason for applying for PT was to inform their offspring about the risk of inheriting HD. Significant differences were observed in the reasons for seeking PT by age group. Although some subjects received treatment, Beck's instrument scores did not indicate special attention or pharmacological treatment. The MMSE showed probable CI in 20 subjects. Of those who received results, 37% were carriers of a full penetrance allele.

Conclusion: Our center has the only formal PT program for HD in Mexico. The reasons for seeking PT are varied and age-related. Although PT is offered to all subjects at risk for HD, uptake remains low.